This page is functional, at least for the part we implemented. And that is exactly what HTML, MySQL and PHP stand for: functionality, not 'look and feel'. That is also why the 'look and feel' of this page leaves something to be desired.
HTML is not rocket science, as a matter of fact, it is quite simple. HTML is about content. It may seem contradictory, but the C in MVC frameworks does not stand for content. The M stand for Model and the C for Control. In that case 'Model' and 'Content' stand for the same. But MVC is for much later. Good to know in the context of all of this, though, is the fact that separation of Model (M), View (V) and Control (C) is now part of the goals for most web design. This principle drives a lot of this demonstration.
The acronym stands for 'Hypertext Markup Language', with markups being the start and end tags in between we put the content. Such as the paragraph you are reading right now, with the text sitting between a <p> and </p> tag.
As said earlier, it is about content. So in HTML the tools for 'look and feel' are limited and using HTML for that is now mostly frowned upon. For instance tools for showing lists or tables are considered part of content. Using them to organize your layout, by organizing the positioning of pictures and other elements with a table is no longer considered acceptable.
MySQL is the database program sitting on the server which hosts the web site. And so is the database itself. The database supporting this web site consists of two tables. One to keep user information, the other to keep content (blogs, comments).
MySQL is open source and free software, originally developed in Scandinavia, Europe. It is now owned by Sun, which has become part of Oracle. So far there is no indication that the take over of Sun by Oracle will affect further support and development of MySQL. The European Union will probably also see to that, as it always puts big take overs under a lot of scrutiny.
MySQL is a typical relational database (RDBM). This means that to avoid duplication you can make links between the records in different tables. For instance when you are logged in and submit a comment or blog entry, your unique user identification is kept in the blog table. That allows to look up, if needed, the other information on the writer based on this identification, in the user table, without having to store it in each record of the blog table itself for each blog entry from that user.
PHP is a programming language which is served up by the web server that hosts the web site. It adds logical control. For instance in HTML we can put together a form of which the HTML says which php program script has to process it when you hit a 'Submit' button. When the data is submitted (posted with an $_POST command), that script can check the validity of the provided input, hand it back to HTML for showing an error message or having the valid data saved by MySQL in its database on the server.
PHP is an object oriented programming (OOP) language, although it was late to follow in the footsteps of other object oriented programming languages. Things to watch out for are that the familiar dot notation (object.property) can not be used in PHP because PHP uses the dot notation for concatenation. Use the -> (object->property) instead. PHP is used a lot for generating HTML code. More about that in the next chapter.
Currently functional links:
Not signing up and not logging in leaves you with username 'anonymous'. Nothing wrong with that, but it will make it difficult to find back your own content in blogs and comments and to leave your email address for us to answer individual questions you leave for us in the blogs or comments.